Intake pipe system for a multicylinder internal combustion engine

ABSTRACT

An intake pipe system for a multicylinder internal combustion engine, in particular one with two cylinder banks arranged to form a V, has a tubular intake distributor 2 from which extends a first set of individual intake pipes 4 to 9 which extend through an arc around the intake distributor and lead to the individual cylinders of the two cylinder banks. A second set of shorter individual intake pipes also extend from the intake distributor and discharge into the associated individual intake pipes. The intake distributor and the first and second sets of individual intake pipes are made up of an integral casting 1 having a longitudinal bore 16 intersecting the second set of individual intake pipes. There is introduced into each longitudinal bore 16 a casing having openings 17 aligned with the second set of individual intake pipes, in which bore a pivoting valve 14 is mounted on a common shaft 20 which is embedded in the casing 15.

DESCRIPTION

The invention relates to an intake pipe system for a multicylinderinternal combustion engine.

In one state-of-the-art intake pipe system of this type (EP-B 0177794,FIGS. 4 and 5) the individual intake pipes are combined with an intakedistributor to form a single unit on which the intake distributor isflange-mounted as a separate component, this intake distributorcommunicating on one side with the intake manifold by way of a throttlevalve element and on the other with the individual intake pipes. Thepivoting valves for the second set of intake pipes are mounted on shaftswhich extend through the intake distributor. This state-of-the-artintake pipe system is relatively costly to manufacture and createsproblems from the viewpoint of reliable interaction of the pivotingvalves mounted in the intake distributor with the second set ofindividual intake pipes mounted in another component.

The object of the invention is to create a generic intake pipe systemwhich is characterized by simplicity of structure and accordingly morecost-effective manufacture and which ensures reliable interaction of thepivoting valves with the second set of individual intake pipes.

Production is simplified by the circumstance that the intake distributorand the individual intake pipes are made up of an integral casting andthe offsets that are virtually unavoidable in the joining of twocastings because of the process tolerances are eliminated. Since thepivoting valves are mounted in a single casing that must be insertedonly into the longitudinal bore in the casting intersecting the secondintake pipe, reliable operation of the pivoting valves in conjunctionwith the second set of individual intake pipes is ensured, and inaddition the possibility is provided of premounting the pivoting valvesfor the second set of intake pipes for all cylinders of a bank ofcylinders. This presents the particular advantage that the shaft bearingthe pivoting valves is mounted in the casing and not, as is the casewith the state-of-the-art design, in the intake distributor on twopoints situated a relatively great distance from each other.

In order to reduce the space required for installation it is advisablefor the intake distributor to be tubular and for the first set of intakepipes to extend through an arc greater than 270° around the intakedistributor and for every other individual intake pipe to extendradially relative to the associated first individual intake pipe on theinside over a partial area of the latter and to have a common wall withthis area and end in the first individual intake pipe near the end ofthe latter on the cylinder side. The longitudinal bore is preferablymounted so that it intersects the second set of individual intake pipesnear its junction with the first set of individual intake pipes.

This design is especially well suited for an internal combustion enginewith two V-mounted cylinder banks, the individual intake pipesassociated with the cylinders of the first cylinder bank extendingclockwise and the individual intake pipes associated with the secondcylinder bank extending counterclockwise around the intake distributor,and in the longitudinal direction of the intake distributor a first anda second individual intake pipe following a first and a secondindividual intake pipe for a cylinder of the second cylinder bank. Afirst longitudinal bore intersecting the second set of individual intakepipes for the cylinders of the first cylinder bank and a secondlongitudinal bore intersecting the second set of individual intake pipesfor the cylinders of the second cylinder bank for the cylinders of thesecond cylinder bank are here provided, into each of which is introduceda casing with apertures, and into the latter pivoting valves mounted ona shaft are inserted. These two shafts are connected to each other in astate-of-the-art arrangement for common rotation.

In order to inhibit as little as possible the process of intake into thesecond set of individual intake pipes, it is advisable to interrupt thesections of the casting between adjacent second individual intake pipesthat contain the longitudinal bores and to design one casing in the areaof these gaps with a cross-section that is smaller in the areas in whichthe openings with pivoting valves are provided.

One example of embodiment of the invention in the form of an intake pipesystem for a V-6 internal combustion engine is described in what followswith reference to the drawings, in which

FIG. 1 shows a longitudinal section of the intake pipe system along line1--1 in FIG. 2, and

FIG. 2 and cross-section along line 2--2 in FIG. 1.

The intake pipe system illustrated in the drawings is designed for a V-6internal combustion engine for mounting between the cylinder banks eachof which contains three cylinders. This system has an integral casting 1containing a central tubular intake distributor 2 that is connectedthrough an opening 3 in the right wall of the casting 1 to a throttlevalve component not shown. Extending from the intake distributor 2 are afirst set of individual intake pipes 4, 5, 6 for the cylinders of thefirst cylinder bank and a first set of individual intake pipes 7, 8, 9for the cylinders of the second cylinder bank. The first set ofindividual intake pipes 4 to 9 are mounted side by side and, as is to beseen from FIG. 2, extend around the intake distributor 2, the first setof individual intake pipes 4, 5, and 6 in Figure two extendingcounterclockwise and the first set of individual intake pipes 7, 8, and9 extending clockwise. The intake openings of the first set ofindividual intake pipes 4 to 9 are identified as 4a to 9a. The first setof individual intake pipes 4 to 6 end in a flange 10 mounted on thecylinder head of the first cylinder bank, while the first set ofindividual intake pipes 7, 8, and 9 end in a flange 11 bolted to thecylinder head of the other cylinder bank.

Mounted radially inside each of the first set of individual intake pipes4 to 9 is a second individual intake pipe 12 which also emerges from theintake distributor 2 and whose intake opening is designated as 12a andwhich ends at 12b in the associated first individual intake pipe, as isto be seen from FIG. 2. The second set of individual intake pipes 12extend parallel to the associated first set of individual intake pipesand in the same direction as the latter and have a common wall 13 withthe latter.

In every other individual intake pipe 12 there is mounted a pivotingvalve 14 which closes off the second individual intake pipe 12 in alower engine speed range, so that only the long first set of individualintake pipes 6 to 9 are active. In the upper engine speed range thepivoting valves 14 are pivoted to their open position, as a result ofwhich in essence only the short second set of individual intake pipesare active and, because of their lower flow resistance, increase thecharging rate and thus the efficiency of the internal combustion engine.

For the purpose of mounting the pivoting valves 14 for the second set ofindividual intake pipes 12 associated with the first set of individualintake pipes 4 to 6 and 7 to 9, which lead to the cylinders of acylinder bank, there is provided a more or less cylindrical casing 15which extends through a cylindrical bore 16 in the casting 1 whichintersects the second set of individual intake pipes 12. The casing 15is provided with openings 17 which are aligned with the second set ofindividual intake pipes and in each of which a pivoting valve 14 ismounted. At its left end as shown in FIG. 1 each casing 15 has a throughbore 19 through which extends a shaft 20 on which the pivoting valvesare fastened. Each of the shafts 20 is axially immobilized in its casingby a pin 21 but is rotatable through a specific angle. The two shafts 20are connected to each other by a rod assembly 22 and are rotatedsimultaneously by a pneumatic motor operator 23.

Mounting the pivoting valves 14 associated with a cylinder bank in thecasing 15 permits preassembly and adjustment of the pivoting valves 14,so that all that is required for mounting the intake pipe system isinsertion of the two casings 15 with the premounted pivoting valves 14into the bores 16 in the casting 1 and immobilization of the twocasings.

The sections 24 of the casting 1 receiving the casings 15 are forcefitted in the intake distributor 2. In order to prevent disruptionthereby of the process of intake into the second set of individualintake pipes, these areas between the individual intake pipes 12 areinterrupted, and each casing 15 is designed with a smaller diameter inthe area of these gaps 26 than in the areas in which the pivoting valves14 are mounted. Consequently, as is to be seen from FIG. 1, each casing15 in essence extends only through the area of the second set ofindividual intake pipes 12 in section 24 of the casting 1.

The invention is not restricted exclusively to an intake pipe system foran internal combustion engine with two V-mounted cylinder banks; it mayalso be applied to an intake pipe system for an internal combustionengine with only one cylinder bank. The first set of individual intakepipes 7, 8, and 9 and the associated second set of individual intakepipes with their valves are, of course, omitted in this instance.

I claim:
 1. An intake pipe system for a multicylinder internalcombustion engine, withan intake distributor (2), a first set ofindividual intake pipes (4 to 9) positioned side by side and extendingfrom the intake distributor and each leading to a cylinder, a set ofshorter second individual intake pipes (12) extending from the intakedistributor (2) and each ending in a first individual intake pipe, andpivoting valves (14) for blocking or clearing the second set ofindividual intake pipes,wherein the intake distributor (2) and the firstand second sets of individual intake pipes (6 to 9 and 12) are made upof an integral casting (1) having a longitudinal bore (16) intersectingthe second set of individual intake pipes (12), and wherein there isintroduced into this longitudinal bore a casing (15) having a centralthrough bore (19) and openings (17) aligned with the second set ofindividual intake pipes (12), in each of which openings a pivoting valve(14) is mounted on a shaft (20) extending through the through bore (19).2. An intake pipe system as claimed in claim 1, wherein the intakedistributor (2) is tubular, the first set of individual intake pipes (4to 9) extend through an arc of more than 270° around the intakedistributor, every other individual intake pipe extends parallel to theassociated first individual intake pipe radially inside which it extendsand has with it a common wall (13) and ends in the first individualintake pipe near the end of the first individual intake pipe on thecylinder side.
 3. An intake pipe system as claimed in claim 1 or claim2, wherein the longitudinal bore (16) intersects the second set ofindividual intake pipes (12) near their junction with the first set ofindividual intake pipes.
 4. An intake pipe system as claimed in claims 1or 2 for an internal combustion engine with two cylinder banks arrangedin the form of a V, wherein the individual intake pipes associated withthe first cylinder bank extend clockwise, and those associated with thesecond cylinder bank counterclockwise, around the intake distributor (2)and in the longitudinal direction of the intake distributor a first anda second individual intake pipe for a cylinder of the first cylinderbank follow a first and a second individual intake pipe for a cylinderof the second cylinder bank, and wherein a first longitudinal bore (16)intersecting the second set of individual intake pipes for the cylindersof the first cylinder bank and a second longitudinal bore (12)intersecting the second set of individual intake pipes (12) for thecylinders of the second cylinder bank are provided, into each of whichbore there is inserted a casing (15) with openings (17) and there areinserted into these openings pivoting valves (14) mounted on a shaft(20), and wherein the two shafts (20) are interconnected for rotation incommon.
 5. An intake pipe system as claimed in claim 4, wherein thesections (24) of the casting (1) between adjacent second individualintake pipes (12) are interrupted, and wherein each casing (15) has asmaller diameter in the area of these gaps (26) than in the areas inwhich the openings (17) with pivoting valves (14) are provided.